The invention is directed to a locking system with components, such as transporting helixes of drilling tools, which rotate and/or strike partially, springs, gearwheels, clutches and couplings, switch levers and the like which can easily be mounted and dismounted and fixed axially on cylindrical shafts.
According to U.S. Pat. No. 4,645,372, a locking system for rapidly mounting and dismounting positive connections on cylindrical shafts consists of the shaft, having an encircling, radial groove, and an external, coaxially disposed sleeve with a radial opening, which contains a locking element in the form of a ball, and, in the locking state, is forced into an axially positive engagement in the groove of the shaft by a locking sleeve, under the tension of a spring, and can be shifted axially.
In U.S. Pat. No. 5,335,947, such a locking system is disclosed, with a locking element in the form of a ball and a locking sleeve, under the tension of a spring, can be shifted axially, and is used for the axially fixed connection of pipes.
Further in DE 19727187 A1, a screw bit is connected over a locking system with the tool shaft of an electrical hand operated tool driving device, and a locking element in the form of a ball engages an inner recess of a sleeve.
In U.S. Pat. No. 4,957,387, a locking element in the form of a ball, in addition to an axially displaceable locking sleeve, providing a positive connection by force, is forced directly into the groove by a peripheral, radially pre-tensioned spring, which temporarily fixes the shaft axially.
It is a primary object of the invention to provide a locking system for a cylindrical shaft, which, dynamically, can be stressed strongly in the axial direction and can be easily mounted and dismounted.
Essentially, the locking system comprises at least one locking element, advantageously in the form of a ball, a shaft with an axially limited, radial recess, for receiving the locking element, and a sleeve. Moreover, the sleeve has a coaxial central opening for the sleeve, and a radially extending insertion opening for the locking element, and an inner and an outer groove located in a common plane extending perpendicular to the sleeve axis and circling at least around half of the circumference. The outer groove supports a radially pre-tensioned spring washer, which has spaced radially inwardly directed legs forming an open sector. The legs are bent radially inwardly towards the inside on either end and extend through radially extending openings of the sleeve into the inner groove.
Advantageously, for reasons of symmetry, two balls are used as locking elements, which advantageously engage two radially facing spherically shaped recesses in the shaft, located diametrically opposite one another.
Furthermore, an external and elongated, axially extending groove is assigned to the openings and permits a pointed dismounting tool to be inserted behind the spring washer.
Advantageously, the outside of the sleeve has a flattened region laterally outwardly of the insertion opening, as a result of which a positive torque can be applied.
The spring washer is pre-installed in the outer groove encircling the sleeve. The two legs of the spring washer extend into the inner groove through the radially extending openings. During locking, the sleeve is pushed over a shaft, especially within a drilling tool, so that the insertion opening lies over a recess, disposed in the shaft of the drilling tool. A ball is inserted and, by rotating the sleeve is guided into the inner groove. By rotating the sleeve further, the ball forces one leg of the spring washer through the openings to the outside. After passing over the ball, the leg then catches behind this ball. While retaining the direction of rotation, the insertion opening is placed over the second recess in the shaft of the drilling tool and the second ball, like the first one, is inserted into the inner groove of the sleeve. Together with the recess of the shaft and the inner groove of the sleeve, the ball forms a positive axially fixed connection. The locking is thus possible without any additional device. For the unlocking, a stiff, pointed device, such as a screwdriver, is required, which engages along the axially extending groove behind the spring washer.
The advantages of the invention lie in the easy handling of locking and unlocking. The locking system can be put statically and dynamically under heavy axial loads and, to a lesser extent; also under high dial loads, which occur particularly drilling percussion drilling. The locking and unlocking can be repeated frequently. Special devices or tools are not required for this purpose.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by it use, references should be had to the drawings and description matter in which there are illustrated and described preferred embodiments of the invention.